Large, thin silicon devices such as solar cells or high power rectifiers must often be bonded to a metal mount in a manner that provides for good thermal and electrical conductivity. It is well known in the art that such bonding may be performed by utilizing an adhesive or by utilizing solder.
Both of these methods suffer from the inability to cope with a mismatch in the linear thermal coefficient of expansion between the silicon and the metal mount. It has been shown (D. L. Olson and K. M. Koliwad, Large Silicon Slice Mounting, IEEE Transactions on Parts, Hybrids, and Packaging, Vol. PHP-7, No. 2, June 1971) that the maximum area of a large silicon slice which may be mounted on a substrate is inversely related to differences in the coefficients of thermal expansion and the change in temperature.
In advanced solar cell systems, mirrors or lenses are used to concentrate sunlight on the silicon photovoltaic cells to levels as high as 100 suns. This high light intensity magnifies the problem of material mismatch between the silicon cell and the metal mounting block.
In earlier, nonconcentrating, solar cell arrays each cell has been mounted either directly on a mounting block or on a single pedestal with flexible interconnects between cells. This practice is exemplified by U.S. Pat. Nos. 2,989,575; 3,769,091; 3,833,425; and 3,837,924. This earlier practice provides for thermal expansion between cells but not for thermal expansion within a single cell.